Curtis Lumber sells Fabral and ABC among others. Here is a link to the Fabral "Blue Book" >>> https://fabral.com/media/1229/pf-blue-book-7-15.pdf the Snow bars are on page 17 if they don't know what they are. Item SB for roofs with plywood sheathing and item SB1 for roofs with purlins. They can order them in any color and amount. I suggest doing runs across the whole roof but will the roof support the snow load that is now going to be retained on the roof? A lot of factors to consider, snow load in the area where the camp is, roof structural framing and condition. If you are confident that the roof is structurally sound I would do a minimum of two rows for 36' of roof length but that is a minimum 3 rows would be ideal. Here is a link to installation for the poly guards >>>> https://fabral.com/media/1991/tb722snowguards1.pdf basically just substitute the snow bars for where the poly guards are located for your size roof. Better order soon, snow is on the way.